Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computer systems (such as touch screens integrated in cellular phones).
Some proximity sensor devices proximity sensor devices utilize microscopic wiring patterns made from opaque conductive materials to form conductive sensor elements. When used over a display of the touch screen, these conductive traces or wires can block some of the pixels or sub-pixels in the display. Certain patterns interfere with the display more than others. For example, if the sensor periodicity is close to the display periodicity, a moiré pattern may be visible when the display is illuminated. Because the eye is more sensitive to some pattern sizes than others, the moiré pattern has a different appearance depending on its size. In the size range of typical displays, small features are less visible. Because of this, fabricators have conventionally attempted to minimize the moiré pattern by reducing the size and width of each conductive trace. Cost effective processing precludes making the conductive traces so small that they cannot be seen under any condition, rendering simple size reduction as an ineffective solution.
Therefore, there is a need for an improved an input device having a plurality of low-visibility sensor electrodes for sensing an input object relative to a sensing region of the input device.